title: Effect of mechanical pressure on the thickness and collagen synthesis of mandibular cartilage and the contributions of G proteins.
abstract: To investigate the role of mechanical pressure on cartilage thickness and type II collagen synthesis, and the role of G protein in that process, in vitro organ culture of mandibular cartilage was adopted in this study. A hydraulic pressure-controlled cellular strain unit was used to apply hydrostatic pressurization to explant cultures. The explants were compressed by different pressure values (0 kPa, 100 kPa, and 300 kPa) after pretreatment with or without a selective and direct antagonist (NF023) for the G proteins. After 4, 8 and 12 h of cell culture under each pressure condition, histological sections of the explants were stained with hematoxylin-eosin to investigate the thickness of the cartilage. Immunohistochemical staining was used to observe type II collagen expressions. The results showed that a hydrostatic pressure of 100 kPa significantly reduced the thickness of the proliferative layer in condylar cartilage without affecting the thickness of the transitional layer. Hydrostatic pressures of 100 kPa and 300 kPa significantly enhanced the synthesis of type II collagen. G proteins are involved not only in the proliferation and differentiation of condylar cartilage regulated by prolonged pressure, but also in the process of collagen production in condylar cartilage stimulated by pressure.
authors.affiliation: Department of General Dentistry and Emergency, School of Stomatology, The Fourth Military Medical University, Xi'an, Shanxi 710032, PR China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Fa-Ming
authors.initials: FM
authors.lastname: Chen
authors.forename: Yong-Jin
authors.initials: YJ
authors.lastname: Chen
authors.forename: Shun
authors.initials: S
authors.lastname: Wu
authors.forename: Xin
authors.initials: X
authors.lastname: Lv
authors.forename: Rui-Ni
authors.initials: RN
authors.lastname: Zhao
mesh_terms: D000818:Animals; D002356:Cartilage / Q000166:cytology* / Q000378:metabolism* / Q000648:ultrastructure; D024043:Collagen Type II / Q000096:biosynthesis*; D019204:GTP-Binding Proteins / Q000378:metabolism*; D008335:Mandibular Condyle / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D011312:Pressure; D051381:Rats; D017207:Rats, Sprague-Dawley; D013314:Stress, Mechanical
chemical_list: D024043:Collagen Type II; D019204:GTP-Binding Proteins